Cholesterol & Alzheimer’s: Is “Good” Cholesterol Not So Good?

First, let’s do a quick recap on cholesterol, and what “good” and “bad” cholesterol are:

• The most common lay understanding (especially under a certain age) is “it’s bad”.
• A more informed view (and more common after a certain age) is “LDL cholesterol is bad; HDL cholesterol is good”.
• A more nuanced view is “LDL cholesterol is established as significantly associated with (and almost certainly a causal factor of) atherosclerotic cardiovascular disease and related mortality in men; in women it is less strongly associated and may or may not be a causal factor”

There’s more to it than that, but that’s the basics that’ll suffice for proceeding onwards to the rest of the article today. If you’d like to learn more about the oft-confused kinds of cholesterol, check out: Demystifying Cholesterol

Broadly speaking, low-density lipoprotein (LDL), or “bad” cholesterol, is generally considered to be… Well… Bad. Specifically because of how it can functionally narrow arteries, causing bits of floating detritus to get stuck in it, narrow it further, and eventually harden into atherosclerotic plaque, at which point it becomes even harder for the body to clear out.

Meanwhile, high-density lipoprotein (HDL) or “good” cholesterol, is considered to be good at least in moderation, because of the observed beneficial effects of a cholesterol ratio that has a higher amount of HDL to a lower amount of LDL.

You can read about that, here: What is a blood cholesterol ratio? And what should yours be?

Sometimes, there will be outliers, for example: The Sardinian Cholesterol Paradox ← in which famously long-lived Sardinians have unusually high LDL levels (but before you reach for the butter, please be aware that there are other factors at hand, so do see the article)

The link between cholesterol and Alzheimer’s (as previously established)

In few words: what’s good for your heart is good for your brain. We’ve written a lot about this before so we’ll not repeat ourselves here, but if you’re “just tuning in”, so to speak, you can catch up here: What’s Your Vascular Dementia Risk?

Now, notably, one of the risk factors for vascular dementia is high total cholesterol. There are tiers of risk:

• High risk: total cholesterol ≥240mg/dL
• Medium risk: total cholesterol 200–239mg/dL
• Low risk: total cholesterol <200mg/dL

Remember, that’s about total cholesterol. That guidance still stands.

However, when we break it down into “good” and “bad” cholesterol…

The link between cholesterol and Alzheimer’s (as newly revealed)

A team of researchers, namely Dr. Sokratis Charisis et al., did a fairly large (n=822) study amongst older adults (mean age 72½ years, standard deviation 3.7 years), of whom, 65.5% women, looking at the breakdown of different kinds of cholesterol, and Alzheimer’s incidence over the course of the study, mean average duration 12.55 years (duration varies per person because as with most longitudinal studies especially of people in this age range, some died before the end of the study).

They found:

• Higher levels of small dense LDL cholesterol (sdLDL-C) were linked to a 21% increased risk of developing Alzheimer’s disease.
• Those with the lowest levels of HDL (“good”) cholesterol were 44% less likely to develop Alzheimer’s compared to those with higher HDL levels.
• Those with sdLDL-C concentrations below the median were 38% less likely to develop Alzheimer’s than those above the median.

In other words,

• having more “bad” cholesterol did increase Alzheimer’s risk, but
• having more “good” cholesterol increased Alzheimer’s risk even more
• having the lowest “good” cholesterol” levels was the most protective factor found in the study

Now, you can see how that still adds up to “higher total cholesterol = higher dementia risk”, but it is a surprise that—in this case—“good” cholesterol is even worse than “bad” cholesterol.

You can read the paper in full here: Association of Blood Lipoprotein Levels With Incident Alzheimer Disease in Community-Dwelling Individuals

What to do about it?

We’ve got you covered; check out:

Ways To Lower Cholesterol Naturally (Without Statins) ← on that page, we do also link to a couple of pages about statin use, if you want to read about that too, but there are reasons (which we explain) why you might want to avoid statins, especially if you’re a woman.

Take care!